There is an another idea of MP-challenge.
Teams starts from the fortified camps located in different parts of the map. The main task - to collect the most number of warpstone's pieces that are scattered across the map, or vice versa this is one huge warpstone located in crater. By the way there is a time limit - something about 15 or 20 minutes.
Players should bring a warpstone's shards in repository of camp as many as they can carry (from 1 piece to 5). Warpstone cause damage to health when character carrying it, and damage as heavy as many shards player carrying. If he dies, shards remain on the place of his death and lighting, so shards are visible and can be collected by other players.
There are NPC-traders in the camp presented alchemist, blacksmith, stableman and condottiere. Alternatively, it could be an only merchant in the camp, which will be presented to all the assorted goods.
There are also several mines and farms that players can take to open access to more advanced things at the NPC in the camp.
Alchemist sells players healing potions and salves. Potion cure N health instantly. Salve cure full HP but for the N period of time. Each potion or salve takes one weapon slot.
Blacksmith sells weapons and armor. Than more mines has been captured, then more advanced weapons and armor are available for sale.
Stableman sells horses. Than more farms has been captured, then more rapid and agile horses are available for sale. Also, than more mines has been captured, then horses are more armored.
Condottiere selling the services of mercenaries. Each player can hire units of various specializations (melee fighters, skirmishers, horsemen). Each type of mercenary claiming the number of captured mines and farms, so than more of these objects has been captured, then stronger mercenaries are available for hiring.
Besides it's possible to make procedure of warpstone's collecting more difficult by adding skeletons' squads around of warstone. So than more team collected shards, than more waves will come to the camp. During game progress skeletons become stronger.
So this MP-challenge is some sort of tactics, RPG and slasher.